Calcium sulfate

CaSO4.tif

Calcium sulfate is a chemical compound with the formula CaSO₄. It is a common laboratory and industrial chemical. In the form of anhydrite (the anhydrous form), it is used as a desiccant. One particular hydrate is better known as plaster of Paris, and another occurs naturally as the mineral gypsum. It has many uses in industry.

Chemical Properties

Calcium sulfate is a white crystalline solid at room temperature. It is poorly soluble in water. The compound exists in three levels of hydration corresponding to different forms:

• Anhydrous form: anhydrite
• Dihydrate form: gypsum
• Hemihydrate form: plaster of Paris

Production

Calcium sulfate can be produced by the reaction of calcium carbonate and sulfuric acid. It is also a byproduct of the desulfurization of flue gases in power stations.

Uses

Calcium sulfate has a variety of uses in different industries:

• In the construction industry, it is used to make plaster, plasterboard, and cement.
• In the food industry, it is used as a coagulant in products like tofu.
• In the medical field, it is used in bone grafting and as a dental impression material.
• It is also used as a desiccant in laboratory and industrial settings.

Health and Safety

Calcium sulfate is generally considered non-toxic. However, inhalation of dust can cause respiratory irritation. Proper safety measures should be taken when handling the compound in its powdered form.

Related Compounds

• Calcium carbonate
• Calcium chloride
• Calcium oxide
• Sulfuric acid

See Also

• Gypsum
• Plaster of Paris
• Anhydrite
• Desiccant